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On Mon, 26 Mar 2012 18:17:32 -0700 (PDT), "hr(bob) "
wrote:

On Mar 26, 7:45Â*pm, "Steve B" wrote:
I have a 21cc hedge trimmer. Â*A Craftsman. Â*It hasn't run for a while, but
the guy swore it was running when put up.

I put new gas in it, and checked the obvious. Â*It needed a new on/off
switch. Â*It has spark. Â*I can't get it to pop, even with shooting a little
gas into the carb, or on the sponge air cleaner.

When I pull the start rope, there isn't very much "POP" at all. Â*I mean
resistance that would come from good compression, or from firing and
igniting the gas/air mixture.

Just how much "POP" should be present, even if you have the switch off, and
aren't trying to start it, but just basically see how much compression it
has? Â*I call "POP" that instantaneous resistance on the pull rope where it
would hit TDC, or fire with a spark. Â*Does two strokes not have the "POP"
that four strokes have because of their different configuration?

Tomorrow, I'll pull the carb and see if there's anything obvious there. Â*The
primer bulb worked, no leakage, and filled up, presumably feeding gas to the
carb.

Steve

If this is a 2-cycle engine, it make take a few pulls to get enough
oil into the unit to raise the compression. you could also put a 1/2
teaspoon oil into the engine thru the spark plug opening, pull the
starter a few times to spread the oil around and then put the plug
back in and see if the compression seems to be higher. You could also
use some starting fluid.
Which WILL wash the oil off the cyl, killing the compression if it
doesn't start right away.